1. Field of the Disclosure
The embodiments disclosed herein relate to a touch sensing device and a method for correcting an output of the touch sensing device capable of increasing sensibility and accuracy of touch sensors.
2. Discussion of the Related Art
With a recent trend toward thin profile and lightness in weight of electric home appliances or personal digital appliances, a button switch as user's input means has been substituted for a touch sensor.
A capacitance type touch sensor, a resistance type touch sensor, a pressure type touch sensor, an optical type touch sensor, an ultrasonic type touch sensor, and the like, are known as the touch sensor. A touch screen is composed of a plurality of touch sensors formed on a display device.
The touch sensors formed on the display device are connected to power lines and are electrically coupled with signal lines of the display device. Hence, much noise is mixed in outputs of the touch sensors. Even if there is no touch input, a deviation between outputs of the neighboring touch sensors greatly appears. The deviation is referred to as a swing level of touch data. A touch signal processing circuit recognizes touch data when the touch data equal to or greater than a predetermined threshold value is input to a sum of a swing level of touch data and noise. As the noise and the swing level of the touch data increase, the sensibility of the touch sensors is reduced. In particular, the sensibility of the touch sensors is affected more by the swing level than by the noise. Accordingly, the swing level of touch data has to decrease so as to increase the sensibility of the touch sensors.
The touch signal processing circuit may include a plurality of integrated circuits, and a deviation between the integrated circuits adversely affects an output between the integrated circuits. As a result, touch recognition error occurs.
The touch signal processing circuit compares previous frame data with current frame data and corrects the touch data depending on a comparative result. However, because frame memories are needed to correct the touch data, the cost of the touch signal processing circuit increases.